As shown in the Functional Block Diagram, the UCC29002 uses an operational transconductance amplifier (OTA) often referred to as a g_M-type error amplifier. The g_M amplifier is chosen because it requires only one pin – the output – to be accessible for compensation. This amplifier generates an output current that is proportional to the difference of its noninverting and inverting input voltages. This output current flows out of the EAO pin and developes an error voltage V_EAO across the current-loop compensation components connected between the EAO pin and ground.

The purpose of the error amplifier (EA) is to compare the output current level of the respective module monitored by the UCC29002 device (represented by V_CSO) to the leader module's current level (represented by V_LS) and generate V_EAO. V_EAO is then used by the Adjust amplifier to adjust the respective module's voltage feedback signal in a way which tends to minimize V_EAO. This process results in nearly-equal output currents among the parallel-operated power supply modules.

In cases where the UCC29002 device assumes the role of the leader load-share controller in the system or it is used together with a stand-alone power module, its V_LS voltage is approximately equal to its amplified current signal V_CSO. To avoid erroneous output voltage adjustment, the input of the error amplifier incorporates an offset to ensure that its inverting input is biased 25mV (typical) higher than its noninverting input. Consequently, when the two input signals to the EA are equal, no adjustment is made and the initial output voltage set-point of the leader module is maintained. The V_CSO of follower modules are necessarily at least 25mV lower than the leader's V_CSO.

The EA output V_EAO is clamped to V_{OH_EA} as specified in the Electrical Characteristics table.